6 1/2's up front anything from 3 1/2 to 5 1/4 rear. Best to remove the stock speakers then use them as reference when you buy new ones. I am runnig 6 1/2's up front with 5 1/4's in the mid panels, however depending on the manufacturer your results will vary as do size interpretations, which are not exact from one name brand to the next and even from model to model. So, like I said, remove your old speakers FIRST and use them as a reference.